Mainboard IPO

The big league of listings

A mainboard IPO is a public issue on the primary boards of the NSE and BSE — the platform for larger, more established companies, subject to SEBI's full eligibility and disclosure regime. It is distinct from the lighter SME platform, which serves smaller firms with relaxed requirements. When you read about a major company "going public," it is almost always a mainboard IPO.

The eligibility bar

SEBI sets demanding criteria for the standard profitability route to a mainboard listing. A company generally needs net tangible assets of at least ₹3 crore in each of the last three years (with no more than half in cash), average operating profit of at least ₹15 crore over the last three years, a net worth of at least ₹1 crore in each of the three years, and post-issue paid-up capital of at least ₹10 crore. These thresholds far exceed the SME platform's lighter bar, which is why the mainboard signals greater scale and scrutiny.

How shares are divided

A mainboard book-built IPO splits the offer among investor categories. Up to 75% can go to qualified institutional buyers (QIBs), including an anchor-investor sub-portion allotted a day before the issue opens. The remainder is divided between non-institutional investors (NIIs/HNIs) and retail investors. Watching how heavily each category subscribes — especially QIBs, the supposed smart money — is one of the clearest reads on genuine demand for an issue.

The boom and a cautionary example

India's IPO market has been red-hot, with 2024-25 seeing record fundraising across both mainboard and SME segments. The marquee mainboard event was Hyundai Motor India in October 2024 — India's largest-ever IPO at about ₹27,870 crore, surpassing LIC. Yet its experience carried a lesson: it was subscribed only about 2.4 times overall, driven by QIBs at roughly 7x while retail was only around half subscribed. Strong institutional appetite did not guarantee a roaring listing, a reminder that size and hype do not always translate into easy gains.

Why it matters. For an investor, knowing an issue is a mainboard IPO tells you it has cleared SEBI's full eligibility and disclosure regime — a meaningfully higher bar than an SME listing, which carries greater risk and lighter oversight. The subscription pattern across QIB, NII and retail buckets, and the company's compliance with these eligibility norms, are essential checks before applying. The mainboard label is reassurance about process, not a promise of profit.